2010年春西南酷旱的监测与机理分析

针对2010年春季我国西南地区出现的严重干旱,采用MODIS数据和TVDI方法对云南省春季旱情进行了监测,揭示了云南省入春以来的旱情动态变化及旱情分布特点。以TVDI作为旱情评价的指标,并结合气象观测的探空资料、天气图以及ncep月平均气温资料和MODIS数据反演大气含水量,分析了导致云南省春旱的地面温湿特征、大气环流特征及大气能量结构特征,提出了此次干旱特殊的形成机理:大气环流、大气能量结构以及地热蒸发等因素的综合作用导致了严重干旱的发生,这对干旱的监测预警提供了有益探索。

Monitoring and Mechanism Analysis of Severe Drought in Southwest China during Spring 2010

A severe drought occurred in Southwest China in spring of 2010 and it resulted in serious economic loss and social problems, especially in Yunnan Province. The distribution and dynamic change of drought are revealed using the TVDI (Temperature Vegetation Dryness Index) based on EOS/MODIS data. Several different types of data, including weather situation, V-3θ diagram, ncep reanalysis data, water content of atmosphere are used to analyze the characteristics of the temperature and humidity on land, atmospheric circulation and energy structure. The results show this severe drought is the result of together with the atmospheric circulation, the air energy structure and evaporating by the land high temperature: 1) Since January 2010, most areas of Yunnan Province experienced the drought, except the Nujiang River Basin in the northwest part of Yunnan Province. 2) The TVDI are sensitive to both the land surface temperature and water content of atmosphere, which lead to the conclusion that it is reasonable to take both of them into consideration when monitoring and evaluating drought. 3) During this severe drought, the vapor content of atmosphere was lower than the multi-year average, as a result of the maintenance of dry northwest wind in the southwest of China. 4) The solar radiation made the temperature of surface increased significantly, leading the relative humidity was low throughout the whole troposphere. These results can provide some theoretical bases and useful references for the forecast and monitoring of the severe drought.